Digital cameras generate image data representative of a scene by the use of a photosensor, which has a plurality of pixels located thereon. Light from the scene is focused onto the pixels, causing each pixel to accumulate a charge. The charge is converted to a number, such as a binary number, for processing. The numbers are sometimes referred to as pixel values. The pixel values representative of the charges accumulated by the pixels may range, as an example, between zero and 255.
If a scene has bright portions, the pixels that image the bright portions may charge to their maximum value or become saturated. Accordingly, the pixel values representative of these pixels will be equal to or close to 255. Any range of brightness that could have otherwise been imaged by these pixels has been lost due to the saturation. These pixels are sometimes referred to as clipped pixels. When the image of the scene is replicated, the portion of the scene represented by the clipped pixels may appear very bright and without any brightness range or fluctuation. Thus, the replicated image appears unrealistic.
Clipped pixels may be the result of a very bright scene or overexposure. For example, bright spots in the image, such as glare, may cause the pixels imaging the bright spots to become clipped. An overexposed image will cause all the pixels to charge for a longer time than they would for a normally exposed image. Thus, all the pixel values will be greater than they would be for a normally or properly exposed image. The result may be that a significant number of pixel values become clipped, causing the replicated image to appear unrealistic.